ARM: mxc: change imx-dma default to_version to 1

The value 0 is not a valid TO version number.  With the current
code, imx-sdma driver will try to load firmware sdma-imx25-to0.bin,
which is obviously not a good name.  Instead, sdma-imx25-to1.bin
makes much more sense.

Signed-off-by: Shawn Guo <shawn.guo@linaro.org>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>